Is there such thing as clear plastic tapping screws?

I doubt that plastic is strong enough to make a tapping screw. It would have to be at least as strong as brass (which is a relatively soft metal).

I’ve been looking too and I can’t seem to find any. I suspect that they might not exist because the process of tapping would likely put too much pressure on a plastic screw, even if you were tapping into plastic, or even a softer type of material. It’s likely that the plastic screw would break during the tapping process.

Not sure what you’re making, but your best bet might be to use a regular metal tapping screw, of the same size (shaft diameter) to tap the hole, then remove the metal screw and put a plastic screw of the same size into the hole. So it would be sort of like creating a machined hole.

You should PM @LuckyGuy, this task is right up his alley.

You should also see if there is a plastics company in your town and ask them about such a product or see if they could custom make something for you, or maybe contact a boat building company, seems like plastic screws would be useful in that business.

@Kardamom Thanks or the advice. First I’ll see of @luckyguy sees this, then I’ll try giving him a PM.

I should mention what I am using these for. I have a plastic display case that needs to be mounted to a wall. The nice thing about the display case is that it is perfectly clear everywhere. Right now I am using metal screws but the metal stands out like a sore thumb so i was looking for something clear like the rest of the case. The display case is not very heavy and it is box shaped and is designed to be mounted with 4 screws so the weight be is not that bad.

Try using some sort of plastic cement.

In that case (no pun intended), you could put anchors into the wall that would provide female machine screw threads, then you could use a polycarbonate or polypropylene screw that has machine threads rather than tapping threads.

Molly anchors could work. You would just use the metal screw that comes with the anchor to expand the anchor, then remove the screw and replace it with the plastic screw. You would probably want to paint the small metal flange of the anchor to match the wall color.

Just to add that for a given size, machine screws are considerably stronger than tapping screws, because the root diameter of the screw is greater. Even if you could find a plastic tapping screw, you’d probably still want to go with the machine screw.

This is a difficult problem. Look here: Properties of materials . You will see that the yield strength of plastics (abs, nylon 66 etc is about the same as wood pine or fir.
Aluminum, which is considered “weak”, is 30 -50 times stronger. Steel is 8 to 10 times stronger than aluminum. All of these numbers are approximate but should give you the idea. Unless you are screwing into something very soft (jello?) I doubt you will find it. Look for Nylon 66 or Delrin.
Have you considered another way of joining the pieces? Ultrasonic welding? UV cured glue?

The only plastic screws I have ever seen were white nylon machine screws that were almost ¼” in diameter, and those screws stripped out pretty quickly since they were on something that had to be removed/replaced occasionally as opposed to assembling it once and leaving it be.

For what you need, adhesives would work far better if for no reason other than shear strength.